如何检查滚动视图是否滚动到底部android工作室

Question

我有Scrollview里面的很多元素。我想检查scrollview是否滚动到滚动的底部。如何实现。请有人推荐我。谢谢。

<ScrollView
    android:id="@+id/scrollview"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_alignParentLeft="true"
    android:layout_alignParentTop="true" >

        <LinearLayout
            android:id="@+id/layout"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical"
            android:showDividers="end|middle" >
                <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="
                 text.......
               " />
               <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="
                  text.......
              " />
        </LinearLayout>
    </ScrollView>

Answer 1

创建自定义滚动视图如下：

公共类CustomScrollView扩展了ScrollView {OnBottomReachedListener mListener;

public CustomScrollView(Context context, AttributeSet attrs,
                    int defStyle) {
super(context, attrs, defStyle);
}

public CustomScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
}

public CustomScrollView(Context context) {
super(context);
}

@Override
protected void onScrollChanged(int l, int t, int oldl, int oldt) {
View view = getChildAt(getChildCount() - 1);
int diff = (view.getBottom() - (getHeight() + getScrollY())) -  view.getPaddingBottom();

if (diff <= 0 && mListener != null) {
    mListener.onBottomReached();
}

super.onScrollChanged(l, t, oldl, oldt);
}

// Getters & Setters

public OnBottomReachedListener getOnBottomReachedListener() {
return mListener;
}

public void setOnBottomReachedListener(
    OnBottomReachedListener onBottomReachedListener) {
mListener = onBottomReachedListener;
}

//Event listener.

public interface OnBottomReachedListener {
public void onBottomReached();
}

}

在您的主要活动中：

CustomScrollView scrollView =（CustomScrollView）findViewById（R.id.scrollView）;

scrollView.setOnBottomReachedListener（new CustomScrollView.OnBottomReachedListener（）{

    @Override
    public void onBottomReached() {
        // ScrollView Reached bottom
    }
});

在您的xml文件中：

<CustomScrollView android:id="@+id/scrollView" android:layout_width="match_parent" android:layout_height="wrap_content" >

</CustomScrollView>

Answer 2

你可以通过比较ScrollView和你的LinearLayout的高度来做到这一点：

ScrollView scrollView = (ScrollView) findViewById(R.id.scrollview);
LinearLayout linearLayout = (LinearLayout) findViewById(R.id.layout);

if(linearLayout.getMeasuredHeight() <= scrollView.getScrollY() +
       scrollView.getHeight()) {
    //scroll view is at the very bottom
}
else {
    //scroll view is in somewhere middle
}

Answer 3

不是说我的是完美的，但它很快，很脏，而且很有效。这是基于这样一个事实：一旦你减速，回收国的状态将会“稳定”，但这本身并不够好，因为任何时候滚动结束都会触发。因此，我们添加了500毫秒的检查，因为一旦你触到底部，'onScrolled'功能就会停止触发，因为你在技术上不会滚动并且会停止更新时间。

        generic_list_frag_recycler_view.addOnScrollListener(object : RecyclerView.OnScrollListener(){
        private var lastPositiveScroll: Long = SystemClock.uptimeMillis()
        // This was implemented to take out the possibility of scrolling up and stopping at the top (negative dy value)
        private var lastScrollWasPositive = false
        override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
            super.onScrolled(recyclerView, dx, dy)
            Timber.d("Scrolled dy: $dy")
            if(dy > 0){
                lastPositiveScroll = SystemClock.uptimeMillis()
                lastScrollWasPositive = true
            }else{
                lastScrollWasPositive = false
            }
        }

        override fun onScrollStateChanged(recyclerView: RecyclerView, newState: Int) {
            super.onScrollStateChanged(recyclerView, newState)
            if(lastScrollWasPositive && newState == RecyclerView.SCROLL_STATE_SETTLING && (SystemClock.uptimeMillis() - lastPositiveScroll > 500)){
                Timber.d("User reached bottom of list!")
                onUserScrollToBottom.invoke()
            }
        }
    })